<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .box {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      align-content: space-between;
      width: 350px;
      height: 300px;
      background-color: pink;
    }

    .box div {
      width: 100px;
      height: 100px;
      background-color: orange;
    }
  </style>
</head>
<body>
  <div class="box">
    <div>1</div>
    <div>2</div>
    <div>3</div>
    <div>4</div>
    <div>5</div>
    <div>6</div>
  </div>
</body>
</html>